This invention is directed generally to a dental capsule for the direct placement of composite type restorative dental material, and more specifically to a unit dose dental capsule for the direct placement of ultra-high density, i.e. packable or condensable composite or heavy viscosity materials to a prepared tooth by syringing.
Dental composite material for restoring teeth was first introduced into dentistry about the mid 1960""s. The initial composites had a paste-like consistency. As a result, dentists encountered considerable difficulty in the placement of such composite material into a prepared tooth. Generally, the dentist would apply such paste-like composite resin material to a tooth by means of a spatula, palate or like tool. This manual technique resulted in the tooth being filled from the outside in. It was noted that this spatula technique of placing such composite resulted in the formation of voids within the finished restoration. This was because the spatula or palate technique of placing such material in a tooth could not satisfactorily pack the paste composite material into the small and difficult to reach areas of the tooth. The placement of such composite material with a palate or spatula also resulted in the entrainment of air and the formation of air bubbles in the composite material as it is being placed. The formation of such voids or air bubbles compromised the strength and durability of the finished restoration. A further difficulty that was encountered by the dentist was that such composite material had a tendency to stick to the palate or spatula, causing the material to be pulled away when the dentist removed the palate or spatula. Also, if a dentist used a metal instrument to place the composite material, there was a tendency of the metallic instrument to react and discolor the composite.
The problems initially encountered by the dentist in placing such composite resins were solved by the development of the syringing technique for the placement of such composite materials. This syringing technique was first disclosed in U.S. Pat. No. 3,581,399 granted Jun. 1, 1971 to Dr. William B. Dragan. The syringing technique and unit dose capsules disclosed in said U.S. Pat. No. 3,581,399 was followed up by other capsule improvements as disclosed in U.S. Pat. Nos. 4,963,093; 4,969,816; 5,083,921; 5,129,825; 5,165,890 and 5,172,807. These known capsule constructions proved satisfactory for placing the composite materials having a paste-like consistency and/or a composite material having a filler content of less than 78% by weight.
Other known capsules from which such paste-like composites could be syringed are disclosed in U.S. Pat. Nos. 4,330,280; 4,384,853; 4,391,590; 4,767,326; 5,100,320; 5,322,440; 5,460,523 and 5,707,234.
Generally, these known capsules are provided with a reservoir portion for containing a predetermined supply of dental material having an internal diameter which is substantially greater than the internal diameter of the discharge orifice. These known capsule constructions have been designed to handle and be used with the then available composites having a paste-like consistency, i.e., a composite resin composition having a filler content of 78% by weight or less. The lower the filler content, the less viscous the material, and the more readily it can be syringed through the relatively small discharge orifice of the known capsule designs.
It has also been observed in the prior known capsule constructions that the arrangement was such that it was never possible to attain total evacuation of the dental material from the capsule so matter how flowable the material. This was because a portion of the material always remained in the nozzle portion of the capsule as the displacement of the plug or piston was limited by the end wall of the capsule. As a result, the portion of the dental material remaining in the nozzle of the capsule was always wasted.
More recently, the composite dental materials are being formulated with a substantially larger filler content, i.e., more than 78% filled whereby such highly filled or ultra dense composites are rendered xe2x80x9cpackablexe2x80x9d or xe2x80x9ccondensablexe2x80x9d to imitate amalgam in consistency. Such ultra dense or condensable composite materials are particularly suitable for restoring the back or posterior teeth. The particular condensable properties of such ultra dense composite materials makes it difficult to dispense from bulk syringes. The extreme viscous properties of such ultra dense dental composites have also prohibited the placement of such ultra dense composite material by the use of the syringing technique utilizing the known capsule constructions, which the dental profession has virtually universally adopted as the preferred method of delivering a composite material directly into a prepared cavity.
An object of this invention is to provide a capsule construction particularly suitable for effecting the placement of ultra dense or highly filled composite resin dental restorative materials by means of the syringing technique.
Another object is to provide a capsule construction for dispensing an ultra dense or packable composite resin material directly to a tooth in a manner to minimize any formation of voids.
Another object is to provide a capsule and plug arrangement which is particularly suitable for packaging and dispensing an ultra dense compactable composite resin material.
Another object is to provide a capsule and plug arrangement constructed so as to insure that the entire amount of material contained in the capsule is completely discharged or ejected from the capsules so as to completely eliminate any waste.
The foregoing objects and other features and advantages are attained by a capsule construction having a generally cylindrical shaped body portion defining a reservoir for receiving a predetermined amount of ultra dense dental composite resin material. The body portion is provided with a full opening at one end with the other end thereof terminating in a nozzle having a discharge orifice disposed at an angle relative to the central longitudinal axis of the body portion. The body portion defining the reservoir is provided with an internal diameter which is equal to or only slightly larger than the internal diameter of the nozzle or discharge orifice. The internal surface or bore of the body portion is uniform and smooth throughout and is connected in communication with the passageway of the nozzle so as to be free of any obstruction to provide for a smooth transition therebetween. The ratio between the internal diameter of the nozzle discharge orifice or opening (d) relative to the internal diameter of the body portion (D) preferably ranges between 1 to 1 to 0.60 to 1. The open end of the body portion is sealed by a displaceable piston or plug which may be spherical, cylindrical or rod-like and/or a combination thereof so as to be rendered bi-directional. Adjacent the open end, the internal surface of the body portion is provided with one or more longitudinally extending venting grooves to facilitate the venting of any entrapped air upon the insertion of the displaceable piston. A laterally extending collar or flange circumscribes the open end of the body portion and a sealing member is fitted to the nozzle for sealing the discharge orifice. In one form of the invention, the displaceable piston comprises a flexible elongated rod which is generally uniform in cross-section so as to be snugly received in the open end of the capsule to seal the material therein which, when displaced, can readily flex about the transition area and slide through the bore of the nozzle to eject all the material from the bore of the nozzle.